The risk factor and the impact on survival of pathological fractures in patients with humeral metastasis

Background Bone metastases often cause pathological fractures, impair patients’ quality of life and survival. Although there are several studies on pathological fractures in femur and spine, currently, there is limited research pertaining to upper limbs. This study aimed to reveal the risk factor and how pathological fractures impact survival in patients with humeral metastasis. Methods This was a retrospective study, based on patients with humerus metastasis treated in Nagoya-City University hospital from 2010 to 2020. Patient characteristics, including sex, age at diagnosis of humeral metastasis, primary cancer, prior treatment, anatomical location and metastatic lesion size were retrieved from the medical records. The patients were divided into the pathological fracture and non-fracture groups, and their background and survival rates were compared. Results A total 31 patients with 32 metastatic lesions were included in this study. Nineteen patients had pathological fractures (one patient had bilateral fractures) and 12 patients had no fractures. The risk factor of pathological fracture was treatment without bone modifying agents in multivariate analysis. The median overall survival was 21 months, 1-year survival was 56% in non-fracture group, and 59% in fracture group. There was no significant difference in survival rate between the two groups, and only chemotherapy had correlation with longer survival in multivariate analysis. Conclusion Bone modifying agents have the benefit of preventing pathological fractures due to humeral metastases. The humeral pathological fracture did not affect patient's survival, and chemotherapy was the only prognostic factor that prolonged survival.